Procedures Never Explained in Textbooks: How to Correctly Convert a Closed-Suction Drain to a Closed-Gravity Drain, and How to Correctly Remove a Closed-Suction Drain Off Suction.

Objective To describe a novel method to convert a closed-system suction drain to a highly efficient closed-system gravity-dependent drain and demonstrate its efficacy in an ex-vivo model. Methods We reviewed the 5 top-selling urology and surgery text/reference books for information on drainage systems. An ex-vivo model was designed with a reservoir of fluid connected to a Jackson-Pratt bulb drain. We measured the volume of fluid drained from the reservoir into the bulb while on-suction and off-suction. This was repeated using a novel modified bulb, where the bulb's outflow stopper was replaced with a one-way valve oriented to allow release of pressure from the bulb. Results With the bulb on-suction, drainage was maintained regardless of the height of the drain relative to the reservoir. With the bulb off-suction, closed passive gravity-dependent drainage occurred only when the drain was below the fluid reservoir; drainage ceased at minimal volumes. With addition of a one-way valve and maintenance of the bulb below the level of the reservoir, drainage proceeded to completion. Conclusion How surgical drains work is not described in the leading urology and general surgery textbooks/reference books. Closed-system suction drains cannot be used to achieve passive gravity-dependent drainage without allowing release of displaced air from the bulb-lumen. The novel modified drain we describe affords reversible closed-system suction and passive drainage.